Nanocarpet Effect:  Pattern Formation during the Wetting of Vertically Aligned Nanorod Arrays

Fan, Jiayan; Dyer, David L.; Zhang, G.; Zhao, Yiping

doi:10.1021/nl048776b

Cited by 129 publications

(136 citation statements)

References 16 publications

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“…The hydrophilicity of NWs and CNTs with water has been widely reported in the literature [13,[17][18][19]. Sessile-drop experiments performed by Ebbesen [20] with water on a CNT bundle showed complete wetting of the capillary channels between nanotubes.…”

Section: Introductionmentioning

confidence: 84%

Assessment of Nanostructured Capillary Wicks for Passive Two-Phase Heat Transport

Ranjan

Garimella

Murthy

et al. 2011

Nanoscale and Microscale Thermophysical Engineering

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The major factors limiting the thermal performance of passive two-phase heat-spreading devices are the ability of the wick structures to transport liquid by means of capillary forces and the thermal resistance posed by the wicks. Nano-scale geometric enhancements to the wick structure, through the use of carbon nanotubes and metallic nanowires, promise to enhance the capillary transport while at the same time decreasing the thermal resistance due to their high intrinsic thermal conductivity. We analyze the performance of nanostructured wicks in heat-spreading applications. We report that the flow resistance of nanostructures constitutes a major barrier to § Author to whom correspondence should be addressed. Phone: +1 (765) 494-5621 2 their use as passive flow-conveying media, and identify geometrical parameters which yield high rates of thin-film evaporation while minimizing the flow resistance. The analysis shows that the use of nanostructures as the sole wicking element in a two-phase thermal spreader restricts its footprint area to a size of 4 cm 2 for heat flux inputs as low as 1 W/cm 2 due to the large flow resistance in the nanowick. To overcome nanowick flow resistance, we propose a nanostructureenhanced sintered particle wick microstructure which leads to a decrease in the wick thermal resistance by 14% relative to the corresponding wick with the same flow resistance and without nanostructures.

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Section: Introductionmentioning

confidence: 84%

Assessment of Nanostructured Capillary Wicks for Passive Two-Phase Heat Transport

Ranjan

Garimella

Murthy

et al. 2011

Nanoscale and Microscale Thermophysical Engineering

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show abstract

“…The pores of nanowire arrays also have a high capillary pressure; however, their relative impermeability compared to microscale wick structures must be carefully assessed in the design process. Further, while the hydrophilicity of NWs and CNTs with water has been reported in the literature [205,206], aligned arrays of nanotubes have also been shown to behave as superhydrophobic surfaces [207]. Hence, surfactants may be used for liquid conveying applications [208], or nanostructures may be functionalized for heat transfer applications via metallization [51], hydrochloric acid treatment [209], or ultraviolet excitation [210].…”

Section: Nanostructured Capillary Wicks For Vapor Chamber Applicationsmentioning

confidence: 99%

Recent Advances in Vapor Chamber Transport Characterization for High-Heat-Flux Applications

Weibel

Garimella

2013

Advances in Heat Transfer

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Owing to their high reliability, simplicity of manufacture, passive operation, and effective heat transport, flat heat pipes and vapor chambers are used extensively in the thermal management of electronic devices. The need for concurrent size, weight, and performance improvements in high-performance electronics systems, without resort to active liquid-cooling strategies, demands passive heat spreading technologies that can dissipate extremely high heat fluxes from small hot spots. In response to these daunting application-driven trends, a number of recent investigations have focused on the design, characterization, and fabrication of ultra-thin vapor chambers for proximate heat spreading away from these hot spots. The predominant transport mechanisms and operational limits have been found to be different under these conditions relative to conventional low-power heat pipes. Noteworthy advances in the fundamental understanding of evaporation and boiling from porous microstructures fed by capillary action, and improvements in vapor chamber characterization, modeling, design, and fabrication techniques are reviewed. Characterization of evaporation and boiling from idealized and realistic wick structures, observation of vapor formation regimes as a function of operating conditions, assessment of fluid dryout limitations, design of novel multi-scale and nanostructured wicks for enhanced transport, and incorporation of these high heat flux transport phenomena into device-level models are discussed. These recent developments have successfully extended the maximum operating heat flux limits of vapor chambers.2

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“…At an aspect ratio (h/2r) of 25 and a packing density p= 50% for the nanopillars, a 51-fold increase in surface area can be achieved. To date, various 3D skyscraper nanostructures have been fabricated using chemical vapor deposition (CVD) (Lau et al, 2003), physical vapor deposition (PVD) (Fan et al, 2004) and template based electrodeposition (Forrer et al, 2000;Wang et al, 2002;Xu et al, 2004). Lately, evidence has emerged to reveal that the nanotubes and nanorods developed by the CVD and PVD techniques could not sustain the capillary forces generated by the nanostructureliquid interaction (Lau et al, 2003;Fan et al, 2004).…”

Section: Design Of High-surface-area Nanostructuresmentioning

confidence: 99%

Design and Fabrication of 3D Skyscraper Nanostructures and Their Application as Electrodes in Biosensors

Zhang¹

2011

New Perspectives in Biosensors Technology and Applications

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Nanocarpet Effect: Pattern Formation during the Wetting of Vertically Aligned Nanorod Arrays

Cited by 129 publications

References 16 publications

Assessment of Nanostructured Capillary Wicks for Passive Two-Phase Heat Transport

Assessment of Nanostructured Capillary Wicks for Passive Two-Phase Heat Transport

Recent Advances in Vapor Chamber Transport Characterization for High-Heat-Flux Applications

Design and Fabrication of 3D Skyscraper Nanostructures and Their Application as Electrodes in Biosensors

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